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  1. #27
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    Jul 2000
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    Guayaquil EC
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    10,427
    Quote Originally Posted by crackertech View Post
    None unless you went past the stop.
    Exactly.

    That's what I meant when I mentioned messing with the adjustment earlier.

    Off-Topic, but I once followed behind a guy who had (for some unknown reason) replaced all six TXVs on an old Hill WIZ wide island frozen food lineup. The owner said this dude had spent a whole day cranking on those valves.

    As it turned out, four of them had been run out past the stop and were then useless. Luckily, the owner had saved the old valves, so I replaced the four bad ones and all was well.

  2. #28
    Join Date
    Sep 2005
    Location
    florida
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    5,514
    Quote Originally Posted by icemeister View Post
    Exactly.

    That's what I meant when I mentioned messing with the adjustment earlier.

    Off-Topic, but I once followed behind a guy who had (for some unknown reason) replaced all six TXVs on an old Hill WIZ wide island frozen food lineup. The owner said this dude had spent a whole day cranking on those valves.

    As it turned out, four of them had been run out past the stop and were then useless. Luckily, the owner had saved the old valves, so I replaced the four bad ones and all was well.

    I love the smell of phosgene first thing in the morning:

    To apply for professional membership click here


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  3. #29
    Join Date
    Mar 2007
    Location
    NW AR
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    2,478
    So I shouldnt be using my 18v impact to adjust the stem? jk. I was/am very gently when adjusting a TXV and didnt go past the stop.

    Despite my intense curiosity to wether its the powerhead or cartridge I think Ill do both at once to save me from having to pump it down and evacuate twice. If it were the slower part of the season Id do one at a time.

    One more question. Say it IS the powerhead and not the orifice, is there a possibility that if I change both Ill end up having to pull the #4 and go back to the #3?

  4. #30
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    Jul 2000
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    Guayaquil EC
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    Quote Originally Posted by ar_hvac_man View Post
    ...One more question. Say it IS the powerhead and not the orifice, is there a possibility that if I change both Ill end up having to pull the #4 and go back to the #3?
    That's why I suggested doing the powerhead first, but from the Btuh requirements I came up with, along with the pulldown requirements as well as a bit of experience, I'd still go with the #4 orifice size.

    I'd estimate the #4 will be around 50% oversized for normal operating conditions, but the valve should end up throttling down quite well at about the 75% range...which should result in better superheat control.

    Did you save the little card that came in the distributor nozzle ziplock bag? It would have the nozzle size stamped on it. I'm just curious, because I've found on a number of jobs the nozzle to be one size too small, which will tend to throw off your TXV sizing.

  5. #31
    Join Date
    May 2004
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    12,145

  6. #32
    Join Date
    Mar 2007
    Location
    NW AR
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    Alright youve convinced me. Ill change the head first.

    I didnt keep the baggie Ive got the other 3 in my hand right now.

    The r-22 nozzles say L 1/2 for med temp and L 3/4 on the other.

    The nozzle in the baggie for all the other various reefers for medium temp application says L 3/4

  7. #33
    Join Date
    Jul 2000
    Location
    Guayaquil EC
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    Quote Originally Posted by ar_hvac_man View Post
    Alright youve convinced me. Ill change the head first.

    I didnt keep the baggie Ive got the other 3 in my hand right now.

    The r-22 nozzles say L 1/2 for med temp and L 3/4 on the other.

    The nozzle in the baggie for all the other various reefers for medium temp application says L 3/4
    If I had to select a nozzle for this job, I'd probably choose an L 1 1/2, going by Heatcraft's procedure.

    If the orifice upsizing fails, you will want to check out that nozzle size. A call to Heatcraft would be a good way to start.

  8. #34
    Join Date
    Mar 2007
    Location
    NW AR
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    2,478
    10-4. Ill begin with the head and go from there. Hope its not the nozzle Ive never had to pull one after brazing in the valve but me thinks it might be a PITA. Thanks for all your time and help. Nice having experts like you guys to fall back on.

  9. #35
    Join Date
    Sep 2005
    Location
    florida
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    5,514
    I still think it's the nozzle.
    I love the smell of phosgene first thing in the morning:

    To apply for professional membership click here


    Educational forums are open.

    If you would like to submit a link or an article or other related info to the EF. click here

  10. #36
    Join Date
    Jul 2000
    Location
    Guayaquil EC
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    Quote Originally Posted by ar_hvac_man View Post
    10-4. Ill begin with the head and go from there. Hope its not the nozzle Ive never had to pull one after brazing in the valve but me thinks it might be a PITA. Thanks for all your time and help. Nice having experts like you guys to fall back on.
    Sometimes getting them out is a real PITA...the retaining clip in particular.

    Quote Originally Posted by crackertech View Post
    I still think it's the nozzle.
    I still think you could be right...if the powerhead and orifice don't cut it.

  11. #37
    Join Date
    Jun 2009
    Location
    DFW, TX
    Posts
    674
    Box at -10*f is cold!!! Would really be sad if you got superheat down to the 4 or 6 degrees your looking for, only to find that now the compressor superheat is below 20 so you have to increase the superheat anyways.... sorry i'm just trying to give you a hard time!!! You're doing the right thing!! Keep at it!

  12. #38
    Join Date
    Apr 2012
    Location
    winnipeg
    Posts
    1,330
    sounds like txv problems... that is if valve receiving solid liquid
    it was working.... played with it.... now its broke.... whats the going hourly rate for HVAC repair

  13. #39
    Join Date
    Jun 2012
    Location
    Tenn
    Posts
    139
    I might have just missed the discharge pressure, but when I change an evaporator, before I get to the fine tune stuff, I use the suction and discharge pressures to set the TXV to pretty close. I also use the scale (mainly to know that I honestly am charging out the right amount of freon), which gives me great confidence that the numbers on my gages do not reflect overcharge or undercharge. If the discharge is high while the suction is dropping, I'm sure you can see where I'm going with this. Depending on the size of the walk in freezer, I may not get to setting the superheat for a few days, yet if I have the correct amount of refrigerant and good suction and discharge pressure, I'm usually pretty close. When setting the rough TXV adjustments, on the occasions that any are required, they are based heavily on the suction and discharge pressure. I am assuming that this walk in has it's own compressor and is not a split type with multiple TXV's, such as a cooler freezer combo.

    I hope that I didn't come across as aggresive. This is my first post

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